Isotope Dilution Analysis
A quantitative technique in which a known amount of labelled isotope is added and the resulting dilution measured.
Formula / equation
n_unknown = n_spike(R_spike/R_mix − 1)
Unit
mol
In depth
Because the added spike and the analyte are chemically identical, any losses during sample preparation affect both equally and cancel out. This makes the method exceptionally accurate and independent of quantitative recovery, so it serves as a reference technique.
Examples in the real world
Determining trace lead in blood by spiking with an enriched lead isotope and measuring the ratio by mass spectrometry.